From 307a0f63dd9b118f4b8470ed3d7567e81fdb7a6d Mon Sep 17 00:00:00 2001
From: Mike Gilbert <floppym@gentoo.org>
Date: Fri, 3 Dec 2021 09:50:31 +0000
Subject: [PATCH] Disable various compiler configs

---
 build/config/compiler/BUILD.gn | 105 ++++++---------------------------
 1 file changed, 17 insertions(+), 88 deletions(-)

diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 5365544..e6d9b56 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -291,9 +291,7 @@ config("compiler") {
 
   configs += [
     # See the definitions below.
-    ":clang_revision",
     ":rustc_revision",
-    ":compiler_cpu_abi",
     ":compiler_codegen",
     ":compiler_deterministic",
   ]
@@ -534,31 +532,6 @@ config("compiler") {
     ldflags += [ "-Wl,-z,keep-text-section-prefix" ]
   }
 
-  if (is_clang && !is_nacl && current_os != "zos") {
-    cflags += [ "-fcrash-diagnostics-dir=" + clang_diagnostic_dir ]
-
-    # TODO(hans): Remove this once Clang generates better optimized debug info
-    # by default. https://crbug.com/765793
-    cflags += [
-      "-mllvm",
-      "-instcombine-lower-dbg-declare=0",
-    ]
-    if (!is_debug && use_thin_lto && is_a_target_toolchain) {
-      if (is_win) {
-        ldflags += [ "-mllvm:-instcombine-lower-dbg-declare=0" ]
-      } else {
-        ldflags += [ "-Wl,-mllvm,-instcombine-lower-dbg-declare=0" ]
-      }
-    }
-
-    # TODO(crbug.com/1235145): Investigate why/if this should be needed.
-    if (is_win) {
-      cflags += [ "/clang:-ffp-contract=off" ]
-    } else {
-      cflags += [ "-ffp-contract=off" ]
-    }
-  }
-
   # C11/C++11 compiler flags setup.
   # ---------------------------
   if (is_linux || is_chromeos || is_android || (is_nacl && is_clang) ||
@@ -1231,45 +1204,6 @@ config("compiler_deterministic") {
     }
   }
 
-  # Makes builds independent of absolute file path.
-  if (is_clang && strip_absolute_paths_from_debug_symbols) {
-    # If debug option is given, clang includes $cwd in debug info by default.
-    # For such build, this flag generates reproducible obj files even we use
-    # different build directory like "out/feature_a" and "out/feature_b" if
-    # we build same files with same compile flag.
-    # Other paths are already given in relative, no need to normalize them.
-    if (is_nacl) {
-      # TODO(https://crbug.com/1231236): Use -ffile-compilation-dir= here.
-      cflags += [
-        "-Xclang",
-        "-fdebug-compilation-dir",
-        "-Xclang",
-        ".",
-      ]
-    } else {
-      # -ffile-compilation-dir is an alias for both -fdebug-compilation-dir=
-      # and -fcoverage-compilation-dir=.
-      cflags += [ "-ffile-compilation-dir=." ]
-    }
-    if (!is_win) {
-      # We don't use clang -cc1as on Windows (yet? https://crbug.com/762167)
-      asmflags = [ "-Wa,-fdebug-compilation-dir,." ]
-    }
-
-    if (is_win && use_lld) {
-      if (symbol_level == 2 || (is_clang && using_sanitizer)) {
-        # Absolutize source file paths for PDB. Pass the real build directory
-        # if the pdb contains source-level debug information and if linker
-        # reproducibility is not critical.
-        ldflags += [ "/PDBSourcePath:" + rebase_path(root_build_dir) ]
-      } else {
-        # Use a fake fixed base directory for paths in the pdb to make the pdb
-        # output fully deterministic and independent of the build directory.
-        ldflags += [ "/PDBSourcePath:o:\fake\prefix" ]
-      }
-    }
-  }
-
   # Tells the compiler not to use absolute paths when passing the default
   # paths to the tools it invokes. We don't want this because we don't
   # really need it and it can mess up the goma cache entries.
@@ -1556,7 +1490,7 @@ config("chromium_code") {
       defines = [ "_HAS_NODISCARD" ]
     }
   } else {
-    cflags = [ "-Wall" ]
+    cflags = []
     if (treat_warnings_as_errors) {
       cflags += [ "-Werror" ]
 
@@ -1565,10 +1499,6 @@ config("chromium_code") {
       # well.
       ldflags = [ "-Werror" ]
     }
-    if (is_clang) {
-      # Enable extra warnings for chromium_code when we control the compiler.
-      cflags += [ "-Wextra" ]
-    }
 
     # In Chromium code, we define __STDC_foo_MACROS in order to get the
     # C99 macros on Mac and Linux.
@@ -1577,15 +1507,6 @@ config("chromium_code") {
       "__STDC_FORMAT_MACROS",
     ]
 
-    if (!is_debug && !using_sanitizer && current_cpu != "s390x" &&
-        current_cpu != "s390" && current_cpu != "ppc64" &&
-        current_cpu != "mips" && current_cpu != "mips64") {
-      # Non-chromium code is not guaranteed to compile cleanly with
-      # _FORTIFY_SOURCE. Also, fortified build may fail when optimizations are
-      # disabled, so only do that for Release build.
-      defines += [ "_FORTIFY_SOURCE=2" ]
-    }
-
     if (is_mac) {
       cflags_objc = [ "-Wobjc-missing-property-synthesis" ]
       cflags_objcc = [ "-Wobjc-missing-property-synthesis" ]
@@ -1988,7 +1909,8 @@ config("default_stack_frames") {
 }
 
 # Default "optimization on" config.
-config("optimize") {
+config("optimize") { }
+config("xoptimize") {
   if (is_win) {
     if (chrome_pgo_phase != 2) {
       # Favor size over speed, /O1 must be before the common flags.
@@ -2026,7 +1948,8 @@ config("optimize") {
 }
 
 # Turn off optimizations.
-config("no_optimize") {
+config("no_optimize") { }
+config("xno_optimize") {
   if (is_win) {
     cflags = [
       "/Od",  # Disable optimization.
@@ -2066,7 +1989,8 @@ config("no_optimize") {
 # Turns up the optimization level. On Windows, this implies whole program
 # optimization and link-time code generation which is very expensive and should
 # be used sparingly.
-config("optimize_max") {
+config("optimize_max") { }
+config("xoptimize_max") {
   if (is_nacl && is_nacl_irt) {
     # The NaCl IRT is a special case and always wants its own config.
     # Various components do:
@@ -2099,7 +2023,8 @@ config("optimize_max") {
 #
 # TODO(crbug.com/621335) - rework how all of these configs are related
 # so that we don't need this disclaimer.
-config("optimize_speed") {
+config("optimize_speed") { }
+config("xoptimize_speed") {
   if (is_nacl && is_nacl_irt) {
     # The NaCl IRT is a special case and always wants its own config.
     # Various components do:
@@ -2125,7 +2050,8 @@ config("optimize_speed") {
   }
 }
 
-config("optimize_fuzzing") {
+config("optimize_fuzzing") { }
+config("xoptimize_fuzzing") {
   cflags = [ "-O1" ] + common_optimize_on_cflags
   rustflags = [ "-Copt-level=1" ]
   ldflags = common_optimize_on_ldflags
@@ -2245,7 +2171,8 @@ config("win_pdbaltpath") {
 }
 
 # Full symbols.
-config("symbols") {
+config("symbols") { }
+config("xsymbols") {
   if (is_win) {
     if (is_clang) {
       cflags = [ "/Z7" ]  # Debug information in the .obj files.
@@ -2369,7 +2296,8 @@ config("symbols") {
 # Minimal symbols.
 # This config guarantees to hold symbol for stack trace which are shown to user
 # when crash happens in unittests running on buildbot.
-config("minimal_symbols") {
+config("minimal_symbols") { }
+config("xminimal_symbols") {
   if (is_win) {
     # Functions, files, and line tables only.
     cflags = []
@@ -2438,7 +2366,8 @@ config("minimal_symbols") {
 # This configuration contains function names only. That is, the compiler is
 # told to not generate debug information and the linker then just puts function
 # names in the final debug information.
-config("no_symbols") {
+config("no_symbols") { }
+config("xno_symbols") {
   if (is_win) {
     ldflags = [ "/DEBUG" ]
 
-- 
2.32.0

